1. Field of the Invention
This invention relates to the separation of cells and the liquid components of blood utilizing a nonparticulate gel mass for the diffusion therein of the liquid components and for the exclusion of blood cells, so that the latter remain for collection.
2. Prior Art
It is known that substances may be separated from one another in time by an elution process utilizing a column packed with gel beads. In such a separation process all of the substances introduced into the column pass through the column. Such processes, referred to as gel filtration or gel permeation, require that the sample to be separated must not contain particulate matter comparable in size or larger than, the gel beads. Otherwise the column would become packed with the particulate matter to prevent the attempted separation. In this manner, blood platelets have been separated from the serum content of a specimen consisting of a mixture of platelets and serum. Platelets are considerably smaller than blood cells which, if introduced into such a column, would clog the column to such an extent as to render the elution process inoperative.
Other uses have been made of a nonparticulate gel mass supported as in a petri dish. One such use is in antibiotic susceptibility tests for example in which the gel is inoculated with microorganism, and a growth inhibitor in the form of a tablet is placed in the gel. Any area of nongrowth around the tablet is indicative of inhibition to growth due to the antibiotic. Another such use is one involving enzyme assays wherein a substrate is dispersed in the gel and reacts with a nonparticulate sample solution which diffuses into the gel for reaction therein. Still another use of such nonparticulate gel masses are antigen-antibody reactions in a typical one of which an antibody is located in the gel and the gel is exposed for diffusion thereinto of a nonparticulate solution of an antigen.
The present invention resides in a new use of such a nonparticulate gel mass, that is for the separation of a blood cell portion from a liquid portion of a whole blood sample. Such separation has heretofore been achieved by centrifugation of whole blood which has required the time consuming and burdensome steps of placing the whole blood sample in a suitable container in a centrifuge machine prior to analysis of the serum or plasma portion in an automated machine for example. Another procedure for such separation has been the settling of a whole blood sample in a well, perhaps, with the use of a settling agent, and then decanting the liquid portion for later use elsewhere in analysis of such liquid portion, as described in U.S. Pat. 3,146,163. However, even the last-mentioned procedure is burdensome to the user. Still another way of achieving such separation has been by utilizing an agglutinating agent in a whole blood sample for agglutination of the cells, which also requires decantation of the liquid portion.
The present invention overcomes these difficulties in the prior art.